The plan to allow households to mix over the Christmas period has 'no scientific basis', according to the resident GP on Good Morning Britain.

Medical expert Dr Amir Khan was speaking to presenters Ben Shepherd and Kate Garraway, one day after the new tier system for England was announced by Health Secretary Matt Hancock and Prime Minister Boris Johnson.

The Christmas plan, agreed by the UK prime minister Boris Johnson and the leaders of the devolved nations in Wales, Scotland and Northern Ireland, will see up to three households be allowed to travel and mix together for five days over the Christmas period.

They can spend time in private homes, places of worship, or public outdoor spaces - but must stick to the same bubble for the five-day period, and can only be in one bubble.

The government advice says: "a fixed bubble is a sensible and proportionate way to balance the desire to spend time with others over the Christmas period, while limiting the risk of spreading infection."

On Good Morning Britain on Friday, Dr Amir Khan, a GP and star of the TV show GPs: Behind closed doors, was asked why giving someone a hug was such a big issue, when the virus can spread by being in the same room as someone. He said: "Opening up households for five days over Christmas is not necessarily a scientific decision, it's more of a political decision.

"Trying to balance it out with the science isn't going to work.

"People in households, they're going to be breathing the same air as one another within that area, so it's a tricky balance.

"There is no scientific basis to it.

"It's more about human behaviour and social decision making."

Presenter Kate Garraway said: "I tell you what I worry about. It's that the people who do try and observe the rules will be anxious about that and won't come together. The people that haven't been will just think, 'blow it', so therefore it makes it very hard for people who tried to stick to the rules."

The GP responded with: "I feel very strongly that opening up households over Christmas is so, so risky. January is going to be so difficult for the NHS, February as well. We're so close to getting these vaccines rolled out.

"It's really frustrating to see this really, to be honest, from a purely health point of view."

Earlier this week, Boris Johnson said of the plans: “Wherever you are in the country I urge you to keep up the incredible effort that you and everyone else have been making to keep pushing the virus down.

“Of course all this means that this year Christmas will be different. Many of us are longing to spend time with family and friends irrespective of our faith or background. And yet we can’t afford to throw caution to the wind.

“The virus doesn’t know it’s Christmas and we must all be careful.”

And the UK government's chief scientific advisor warned at a press conference on Thursday night that hugging could have severe consequences.

Professor Chris Whitty stressed that people should not have such a tactile approach with loved ones this festive season “if you want them to survive to be hugged again”.

He said: “Would I want someone to see their family? Of course, that’s what Christmas is about, whether people celebrate Christmas as a festival themselves or from any other belief system. It is an opportunity for families.

“But would I encourage someone to hug and kiss their elderly relatives? No, I would not.

“It’s not against the law, and that’s the whole point. You can do it within the rules that are there but it does not make sense because you could be carrying the virus and if you’ve got an elderly relative, that would not be the thing you want to do in the period where we’re running up to a point where actually we might be able to protect older people."

Commenting on what Chris Whitty said, GP Amir Khan added on GMB: "This idea of having a five-day break over Christmas, we understand the psychological need of the country for that, but without doubt it is a risky process.

"I agree with Professor Whitty, we shouldn't be hugging vulnerable people.

"The reality is this isn't a normal Christmas. As much as we like it to be, this can't be a normal Christmas."

And a member of the Government’s Scientific Advisory Group for Emergencies (Sage) warned it could lead to a third wave of the pandemic.

Professor Andrew Hayward told BBC2’s Newsnight: “Effectively what this will be doing is throwing fuel on the Covid fire.

“I think it will definitely lead to increased transmission. It is likely to lead to a third wave of infection, with hospitals being overrun, and more unnecessary deaths.

“With the vaccine on the way, if we are not very careful over Christmas we are really in danger of snatching defeat from the jaws of victory on this one.”